Soil / tent have musty mildew smell

[Phate008]

I posted a 1-2 weeks ago. My plants felt stunted and my humidity was too low. I ended up watering more bringing it from 1 quart to about 2 - 2 1/2 quarts per plant. This brought my humidity back up to a good zone and the plants took off. They grew vigorously and then humidity took a turn in the other direction. The past couple days the humidity was at 62-64% and 70-75 degrees in the tent. I originally just had the pots sitting flat in trays, but I decided to buy pot elevators to keep them out of any run off and get better air circulation to the roots. I installed the pot elevators and gave them their first feeding top dressing of Dr Earth Bloom at week 7. 2 days later and I opened the tent to a musty smell. Today the smell was still there. The top of the soil was dry (pots light) and I watered again. Musty smell still there. Its not really effecting the plants yet, they all look nice and healthy. The smell is coming from the soil. I am guessing I need to treat the soil with something to kill mildew or transplant them. Also for sure should decrease the humidity with a dehumidifier. The smell is the same as when you accidentally leave a load in the laundry machine and you discover it the next day with that musty mildew smell. I planned on cloning these plants tomorrow and then flipping them to flower in about 5-6 days. What are my options? Advice or suggestions are welcome.

5 Plants in a 4x4 tent, growing in 5 gallon fabric pots with fox farm ocean forest soil. Watering every 3 days for the last couple weeks.

EDIT: Before lights out tonight I increased the fan speed on the exhaust to 8. I added 2 more fans. One small fan and 1 large dyson bladeless fan. I think the stagnant humid air and possibly over watering are the cause. Is there any way to kill mildew in soil. Should I replant with fresh soil? Clone all the branches and scrap these plants? Not sure what to do. These first 2 grows have not been easy for me.

 

[AKgrow]

Let them dry out, increase airflow under the canopy, lower humidity. Sounds like you are on the right track, read up on watering practices and keep learning from your grows. A picture?

 

[Phate008]

I posted a pic of them from yesterday. Before the lights went out I noticed the healthiest/largest one was dropping a bit. Definitely think I was over watering. Probably should be waiting closer to 4-5 days with 5 gallon pots.

 

[Phate008]

So I think it is only 2 plants having this issue. Definitely an over watering issue possibly beginning stages of root rot from what I have read. I would prefer not to have to take them out of the pot, cut off bad roots, and repot. I am going to wait 5-7 days and let the medium get bone dry. With the extra fans, better intake fan, and exhaust fan set to high I have managed to get my humidity down to 58%.

I say it's root rot not just because of the smell, but also because of the signs on 2 of the plants. On one plants the leaves are turning a pale green color. On the other the leaves are yellowing slightly and crunching up and wrinkling. The other 3 plants look great and have still been growing bigger by the day. I have probably been over watering since my last post on here. I have been giving them 2 quarts every 3 days like clock work. This may have been fine for the larger plants, but the smaller ones weren't drinking it fast enough. They are in 5 gallon pots so while it may have seemed dry on the surface, the bottom half was probably maintaining a lot of moisture. This combined with the lack of pot elevators may have made the bottom stay damp. I am not sure how well fabric pots release liquid. I used to never see runoff, but I was watering on this go until I saw a small amount of water coming out of the bottom.